ANATOMY OF

THE HEART
dr. Aditya Reza Pratama
dr. Yusuf Arifin

dr. Sasmojo Widito, Sp.JP (K)

• Pericardium:
• Outer fibrous sack
• Myocardium:
• Thick muscle walls
• Endocardium:
• Innermost surface
• Simple squamous epithelium

Anatomy of the Heart

• Heart chambers :
• Left & Right atria
• Left & Right ventricles
• Heart valves :
• Atrioventricular valves;
• Right : Tricuspid
• Left : Bicuspid/ Mitral
• Semilunar valves;
• Right : Pulmonary valve
• Left : Aortic valve

Anatomy of the heart

 Myocardial Cell

• Multiple parallel myofibrils

surrounded by mitochondria
• The T tubules are invaginations
of the cell membrane (the
sarcolemma)
• Sarcoplasmic reticulum houses
most of the intracellular calcium
and abuts the T tubules

Each myofibril consist of serially

connected sarcomere from one z
line to the next

Sarcomere is composed of
alternating thin (actin) and thick
(myosin) myofilaments
• The wall of the heart are composed of a thick layer
of cardiac muscle, the myocardium
• The muscle fibers of the heart are arranged in
different direction, could be oblique, tranverse or
longitudinal
• Atrial fibers are arranged in two layers,
• Superficial layer is Transverse
• Deep layer is looped and annular
• Ventricular fibers are also arranged in two layers
• Superficial layer Spirally (clockwise as seen from
the apex)
• Deep layer consist of horizontal bundles in S-
shape
Cardiac Muscle
Orientation of Cardiac Muscle Fiber
• Unlike skeletal muscle,
cardiac muscle have to
contract in more than
one direction

• Cardiac muscle are

stiated, meaning they
will only contract along
their long axis

• In order to get
contraction in two axis,
the fibers wrap around
 Anterior View Posterior View

Right Atrium Tranverse fibers = 84% Right Atrium Transverse fibers = 100%

Longitudinal fibers = 16%

Left Atrium Transverse fibers = 100% Left Atrium Transverse fibers = 100%

Right Ventricle Transverse fibers = 84% Right Ventricle Transverse fibers = 88%

Oblique fibers = 16% Oblique fibers = 12%

Left Ventricle Oblique fibers = 100% Left Ventricle Transverse fibers = 24%

Oblique fibers = 76%

• Cardiovascular function is controlled by
the Central Nervous System (CNS)
• Medulla Oblongata, hypothalamus,
korteks
• Parasympathetic
• The parasympathetic innervation arrives to the
heart by means of branches of the vagus nerve
• Sympathetic
• The preganglionic sympathetic fibres innervating the
heart are the axons of cells located in the lateral
grey columns of T1-T5 segments of the spinal cord

Cardiac Innervation
 • Length of postganglionic fibers
• Sympathetic – long postganglionic fibers
• Parasympathetic – short postganglionic fibers
• Branching of axons
• Sympathetic axons – highly branched
• Influences many organs
• Parasympathetic axons – few branches
• Localized effect

Anatomical Diffences in Sympathetic and

Parasympathetic Divisions
Autonomic Innervation
 • Neurotransmitter released by preganglionic
axons
• Acetylcholine for both branches (cholinergic)

• Neurotransmitter released by postganglionic

axons
• Sympathetic – most release norepinephrine
(adrenergic)
• Parasympathetic – release acetylcholine

Neurotransmitters of
Autonomic Nervous System
• Both the parasympathetic and sympathetic nerves
form the superficial and deep cardiac plexuses
• Superficial cardiac plexus - situated below
the arch of aorta in front of the right pulmonary
artery, it is formed by –
• The superior cardiac branch of superior cervical ganglion of
the left sympathetic chain and
• The cardiac branches from inferior cervical region ( inferior
cervical nerves ) of the left vagus nerve.
• It gives branches to
• The deep cardiac plexus
• The right coronary artery ( coronary plexus ) and
• The left anterior pulmonary plexus.

Cardiac Plexus
• Nerve supply Features
1. Sympathetic innervation More at the base than
the apex
2. Vagal activity Greater in posterior
and inferior wall
3. Rt sympath. and vagus Affect SA node > AV node
4. Lt sympath. and vagus Affect AV node > SA node

Peculiarities of nerve supply to the heart

 Sympathetic nerve – noradrenergic fiber;
Parasympathetic nerve- cholinergic fiber
 Noradrenergic sympathetic nerve
 to the heart increase the cardiac rate (chronotropic
effect)
 the force of cardiac contraction (inotropic effect).
 Cholinergic vagal cardiac fibers decrease
the heart rate.
• Most important adrenoreceptor is heart is B1
• B2 adrenoreceptor in heart has similar cardiac effect B1
• Prejunctional a2 adrenoreceptor inhibit NE release
• Prejunctional b2 adrenoreceptor facilitate NE release
• Prejunctional M2 adrenoreceptor inhibit NE release
• Right atrium – 74% b1 and 26% b2
• Ventricles – 86% b1 and 14% b2

Cardiac Receptor
Intracardiac
Pressures
• Pressures recorded from catheter tip
• Electrical transducer - wheatstone bridge•
• Mechanical to electrical waveform
• Display - ECG, Intracardiac pressures, O2 sat.

Principle
• Measure intracardiac pressures
• Assess intracardiac blood flow
• Assess ventricular function
• Determine cardiac anatomy
• Assess valvular function
• Assess pulmonary and systemic circulatory systems

Purpose
Cardiac cycle

Mann, 2015
 Pressure Recordings
 Always record pressure at end expiration (except in patients on PEEP)
 Under normal conditions, pressures will be lower in inspiration due to
decrease in intrathoracic pressure
 PCWP reflects left atrial pressure and hence the left ventricular end diastolic
pressure as long as ventricular compliance is normal or unchanging
 PCWP > LVEDP: Mitral valve stenosis or regurgitation, left atrial
myxoma, pulmonary vascular disease/embolism, increased pulmonary
vascular resistance, cor pulmonale
 PCWP < LVEDP: Early stages of diastolic dysfunction, aortic
regurgitation, decreased ventricular compliance due to myocardial
ischemia/infarction, positive pressure ventilation, etc.
Site Normal Values Mean Pressure
(mm Hg) (mm Hg)
Right Atrium 0-8 4
Right Ventricle 15-25/0-8 5-12
Pulmonary Artery 15-25/8-12 10-20
PCWP 9-23/1-12 6-12
PCWP = Pulmonary Capillary Wedge Pressure
 Time (msec)  0 100 200 300 400 500 600 700 800

Cardiac Cycle QRS

Complex

EKG P T
P

Left Sided
Pressures
120

Aorta
9
0 Dicrotic
Pressure Notch
(mm Hg)

6
0 Left Ventricular
Pressure

3
v
0 c
Left Atrial a
Pressure y
x
0

Atrial Ventricular Systole Ventricular Diastole

Systole
 Time (msec)  0 100 200 300 400 500 600 700 800

Cardiac Cycle QRS

Complex

EKG P T
P

Right Sided
Pressures
30

PA Pressure

Dicrotic
Pressure Notch
(mm Hg)

1
5 Right Ventricular
Pressure

v
c
Right Atrial a
Pressure y
x
0

Atrial Ventricular Systole Ventricular Diastole

Systole
 Pressure Wave Interpretations
RA/ PCWP
Wave pattern Mechanism Condition
Cannon ‘a’ wave AV dissociation Complete heart block, ventricular
tachycardia, AVNRT
Tall ‘a’ wave Increased atrial pressure Mitral or tricuspid stenosis
No ‘a’ wave Loss of atrial kick Atrial fibrillation
Tall ‘v’ wave Increased volume during Mitral or tricuspid insufficiency,
ventricular systole VSD
Loss of ‘y’ descent Equalization of diastolic Cardiac tamponade
pressures
Exaggerated ‘y’ Rapid diastolic filling Constrictive pericarditis
descent
AVNRT = Atrioventricular Nodal Reentry Tachycardia; VSD = Ventricular Septal Defect